Hi Pete,
Just replied to your email.
And thanks for all the other bits, I've got about 50(ish) photos from the McChesney wanderings, on both sides of the watershed but mostly around Troutbeck. Nothing underground but does cover quite a few sites and a short article Anne wrote for one of Moor House's annual reports.
Jim
Correction now done c/o Mr Mike, what a good guy.
Just to add to the somewhat confused picture, as mentioned above Don suggested it could be Gilbert's Level, also known as New Silverband (Geol. of Moor House p. 100), which seems to coincide with Middle Tongue mine. Based on christwigg and brooks pics this adit is not the same.